Is this available anywhere? (Homebrew ROM to display memory)

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Dugongue
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Is this available anywhere? (Homebrew ROM to display memory)

Post by Dugongue » Thu Mar 07, 2019 6:41 pm

Does there exist a ROM that simply displays a section of memory from their initial state at bootup? For example, displaying the range of $000-$FFF in a scrollable list. I've been curious to investigate games that use unitialized memory, & it occurs to me if such a ROM existed & were manufactured into a cart I could experiment with it on multiple consoles & do research on the relevant memory addresses.

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rainwarrior
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Re: Is this available anywhere? (Homebrew ROM to display mem

Post by rainwarrior » Thu Mar 07, 2019 6:49 pm

I wrote this a few years ago: ram_retain.nes

jroatch's coredump might be better though: here

A lot of times ROMs of this nature can be found organized here: Wiki: Emulator tests

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tokumaru
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Re: Is this available anywhere? (Homebrew ROM to display mem

Post by tokumaru » Thu Mar 07, 2019 7:01 pm

Dugongue wrote:For example, displaying the range of $000-$FFF in a scrollable list.
The NES only has RAM at $000-$7FF though. $800 and up, until $1FFF, contains mirrors of $000-7FF.

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koitsu
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Re: Is this available anywhere? (Homebrew ROM to display mem

Post by koitsu » Thu Mar 07, 2019 8:35 pm

Dugongue wrote:Does there exist a ROM that simply displays a section of memory from their initial state at bootup? For example, displaying the range of $000-$FFF in a scrollable list. I've been curious to investigate games that use unitialized memory, & it occurs to me if such a ROM existed & were manufactured into a cart I could experiment with it on multiple consoles & do research on the relevant memory addresses.
What research do you wish to do on the system RAM from $0000-07FF?

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Re: Is this available anywhere? (Homebrew ROM to display mem

Post by JRoatch » Thu Mar 07, 2019 9:21 pm

Action 53 Volume 3 from INL contains coredump, and is currently available for purchase. With it, just hold A and B when booting the NES to show unitialized memory.

Though if you wanted to investigate the games themselves instead of the system, it's best to use the debugger in Mesen which has a menu option to break* on unitialized memory reads.

*break means to set a condition on which to pause and show what instruction was responsible.

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